In the past, liquid bath vacuum cleaners have been used to mix cooling air and cleaning air during the cleaning process. A typical example of a liquid bath vacuum cleaner is disclosed in U.S. Pat. No. 4,640,497, issued Feb. 3, 1987, in the name of Erickson, Jr. This patent discloses a liquid bath vacuum cleaner having a cooling air stream separated from its cleaning air stream to improve the cooling efficiency of the vacuum cleaner. The vacuum cleaner includes a separator at one end of the drive motor and a fan at the other end.
Such vacuum cleaners frequently utilize a cooling fan to exhaust cooling air axially from the fan. Since there is no radial component of the air leaving the fan, the air will take a longer time period to reach the drive motor. Also, there is less blade area on axial flow fans which limits the amount of airflow that can be exhausted to the drive motor. Furthermore, if a fan producing a larger air flow is to be installed in existing vacuum cleaners, typically, the vacuum cleaner would have to be modified to accommodate this fan.
Accordingly, the subject invention is a vacuum cleaner including a housing having an assembly for cleaning the air. A cap assembly is operably the cap assembly. A motor is mounted within the canister for rotating the assembly for cleaning the air. The cap assembly includes an inlet for enabling ingress of cooling air into the cap assembly and an outlet for enabling egress of cooling air from the cap assembly. A motor cooling fan is connected to the motor for drawing cooling air through the inlet and for exhausting the cooling air radially and axially from the motor cooling fan to cool the motor and exhaust the cooling air through the outlet.
The subject invention provides an additional radial component of cooling air flow. The cooling fan exhausts the air in a straight line path substantially parallel to the longitudinal axis of the motor drive shaft. Since the exhausted air flows directly to the motor, less time is required for the cooling air to reach the drive motor. This feature results in an improved efficiency in cooling the drive motor which may then be combined for even greater cooling efficiency. Finally, the subject invention produces an increased air flow and may be installed in existing vacuum cleaners without modifying the vacuum cleaner.